Separation fences are used in a hydrometallurgical liquid-liquid solvent extraction settler to enhance coalescence of the dispersion. In the VSF® technology (stands for Vertical Smooth Flow) developed by the applicant the separation fences are so-called DDG® fences (Dispersion Depletor Gate) (disclosed e.g. in document U.S. Pat. No. 7,517,461).
In prior art, the separation fence is typically manufactured of a fibre-reinforced plastic composite (FRP) by hand laminating. The fence fabricated by hand lamination has many disadvantages. Hand lamination makes the surfaces of the fence, which are in contact with the liquid flow, rough and the edges sharp so that vortices and dead areas are created in the flow. Sharp edges cause unwanted eddies, spouts and jets. This causes scale build-up on flow patterns and the fence is trapping crud. The cleaning of the fence is time-consuming and cumbersome. The liquid flow on the rough surfaces and sharp edges of the fence also causes electrostatic charging which may cause igniting of the flammable atmosphere in the settler. Ignition of the volatile organic compounds (VOC), which are released from the hydrocarbon based solvents, can occur if sufficient electrostatic energy is released in a static discharge. As a manufacturing method of the fence, hand lamination is slow, costly and vulnerable to poor craftsmanship. In hand lamination, also air bubbles may easily remain inside the structure, weakening the fence structure.